Hidden dangers in the production and processing of all-welded ball valves

Release time:

2020-03-18

In the design of the valve body welding joint, in order to align and position

Hidden dangers and points to note in the production and processing of fully welded ball valves. In the design of the valve body welding joint, in order to align and position, there is an annular assembly gap at the root of the weld seam. Under the action of internal pressure and external load, this gap will produce stress concentration several times higher than the normal working stress, which is also difficult for engineers to handle.
The stress concentration, residual stress, and deterioration of the root gap of the welded joint of the fully welded ball valve body have become a weak link in the valve body structure, attracting attention from the domestic and international valve industry, but there are no relevant reports on solving this problem, which is a hidden danger to the structural integrity of this product.
The thick-walled multi-layer welding process is a process in which the metal material is repeatedly heated and cooled multiple times, leading to the inhomogeneity and deterioration of the welded joint structure, generating high residual stress, and even welding defects. Welding is the last process after the assembly of this product. There are non-metallic sealing materials such as rubber and polytetrafluoroethylene plastic in the valve cavity, which cannot be subjected to post-weld heat treatment.